RE: FW: xAP configuration protocol

[Kevin Hawkins]

<div class="Section1">
<p class="MsoNormal"><font size="2"
color="navy" face="Arial"><span>Hi Silvan
&#8211; sorry for misspelling your
name earlier &#8211; and welcome &#8211; just picked up on your
email address !&nbsp; </span></font></p>
<p class="MsoNormal"><font size="2"
color="navy" face="Arial"><span>Are you using
xAP already with the ExStreamer
connector ??</span></font></p>
<p class="MsoNormal"><font size="2"
color="navy"
face="Arial"><span>&nbsp;</span></font></p>
<p class="MsoNormal"><font size="2"
color="navy"
face="Arial"><span>&nbsp;</span></font></p>
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<p class="MsoNormal"><font size="2"
face="Tahoma"><span lang="EN-US">-----Original
Message-----
<b><span>From:</span></b> Silvan Sauter
[mailto:silvan@xxxxxxx]
</span></font><span
lang="EN-US">&nbsp;</span>
&nbsp;
<font size="2" face="sans-serif"><span>i
think the target=UID in the header does not exist, right? so we would have
to
do something that you can target a device by its
address.</span></font> </p>
<p class="MsoNormal"><font size="2"
color="navy" face="Arial"><span>Yes
&#8211;
you can&#8217;t target a UID &#8211; there are some very good
reasons for this that are
discussed in the archives here if you want to know the reasoning behind
this&#8230;</span></font></p>
<p class="MsoNormal"><font size="3"
face="Times New Roman"><span>

</span></font><font size="2"
face="sans-serif"><span>if the device exists in the
network it would answer
with it's heartbeat.</span></font>

<font size="2" face="sans-serif"><span>the
problem we have here in general are the devices that do not support sending
a
hb and i think this is something that would have to be mandatory if the
protocol goes into this direction. as kevin is saying, if a device does not
support a hb, nobody knows that it is there. with the
</span></font><font size="2"
face="sans-serif"><span>PING</span></font><font
size="2" face="sans-serif"><span>
command we could actually force a device to send its
hb.</span></font> </p>
<p class="MsoNormal"><font size="3"
face="Times New Roman"><span>
</span></font><font size="2"
face="sans-serif"><span>as for the rest of this autoUID
thing we could use
standard xAP messages. the device that is new on the network would send a
device.new message and deliver all the parameters that can be configured
with
there actual values to the network.</span></font>

<font size="2"
face="sans-serif"><span>xAP.header</span></font>

<font size="2"
face="sans-serif"><span>{</span></font>

<font size="2"
face="sans-serif"><span>&nbsp;
&nbsp; &nbsp; &nbsp; ...</span></font>
<font size="2"
face="sans-serif"><span>}</span></font>

<font size="2"
face="sans-serif"><span>device.new</span></font>

<font size="2"
face="sans-serif"><span>{</span></font>

<font size="2"
face="sans-serif"><span>&nbsp;
&nbsp; &nbsp; &nbsp; uid=nnddddsss</span></font>
<font size="2"
face="sans-serif"><span>&nbsp;
&nbsp; &nbsp; &nbsp;
location=location</span></font>
<font size="2"
face="sans-serif"><span>&nbsp;
&nbsp; &nbsp; &nbsp;
target=vendor.device.instance</span></font>
<font size="2"
face="sans-serif"><span>&nbsp;
&nbsp; &nbsp; &nbsp; parameter0=xx</span></font>
<font size="2"
face="sans-serif"><span>&nbsp;
&nbsp; &nbsp; &nbsp; parameter1=yy</span></font>
<font size="2"
face="sans-serif"><span>}</span></font>


<font size="2" face="sans-serif"><span>a
configuration application could now take all these parameters and let the
user
change them and send a config.set message back to the
device.</span></font>

<font size="2"
face="sans-serif"><span>xAP.header</span></font>

<font size="2"
face="sans-serif"><span>{</span></font>

<font size="2"
face="sans-serif"><span>&nbsp;
&nbsp; &nbsp; &nbsp; ...</span></font>
<font size="2"
face="sans-serif"><span>}</span></font>

<font size="2"
face="sans-serif"><span>config.set</span></font>

<font size="2"
face="sans-serif"><span>{</span></font>

<font size="2"
face="sans-serif"><span>&nbsp;
&nbsp; &nbsp; &nbsp; uid=newuid</span></font>
<font size="2"
face="sans-serif"><span>&nbsp;
&nbsp; &nbsp; &nbsp;
location=newlocation</span></font>
<font size="2"
face="sans-serif"><span>&nbsp;
&nbsp; &nbsp; &nbsp; target=newtarget</span></font>
<font size="2"
face="sans-serif"><span>&nbsp;
&nbsp; &nbsp; &nbsp;
parameter0=newparameter0</span></font>
<font size="2"
face="sans-serif"><span>&nbsp;
&nbsp; &nbsp; &nbsp;
paramteter1=newparameter1</span></font>
<font size="2"
face="sans-serif"><span>}</span></font>


<font size="2" face="sans-serif"><span>in
addition there would also be a config.get message that brings back the
configuration parameters for a known device.</span></font>

<font size="2" face="sans-serif"><span>the
only dicussion that hinders us to do something like this are the
only-senders,
because these devices would have to support a device.ping message, right?
for
this i have a few questions anyway. it is right that these xAP only sender
devices are most likely RS232 devices? i assume that an ethernet device
would
be enough powerful to support to receive
messages</span></font></p>
<p class="MsoNormal"><font size="2"
color="navy" face="Arial"><span>This is
problematic &#8211; realistically some small devices just wont be
senders (or can&#8217;t
for codespace reasons) &#8211; plus some xAP applications are non
persistant &#8211; they start
up based on a trigger of some form, send their data and then close
&#8211; see the adjacent
posts. That means even PC applications may not support this
&#8216;ping&#8217; type of
operation. Have a peek at Mark&#8217;s adjacent post re Outlook for
example. Stuart&#8217;s
SEND application is slightly less problematic in that it could be made
persistant
although it serves no purpose to do so &#8211; and just eats resources.
To an extent
his container application could also handle heartbeats too on behalf of
such
clients. A sender could register with the container. Or a container could
reserve some UID&#8217;s for such apps in
advance.</span></font></p>
<p class="MsoNormal"><font size="2"
face="sans-serif"><span>. also for RS485 devices, i
assume they have to have some kind of collision detection on the network,
to
figure out if it can send a message or if someone else is sending (standard
multimaster problems on RS485 networks). if there are only RS232 devices,
how
are they managed. there has to be a gateway that connects the RS232 device
to
another network since RS232 is only PtP. if this is the case then maybe the
gateway has to be able to support a </span></font><font
size="2"
face="sans-serif"><span>PING</span></font><font
size="2" face="sans-serif"><span>
command of its dumb RS232 device.</span></font> </p>
<p class="MsoNormal"><font size="2"
color="navy" face="Arial"><span>I understand
what you&#8217;re saying here &#8211; that a gateway could take
over responsibility for heartbeats
where there is one client &#8211; but to an extent we don&#8217;t
care about how many
devices are on the network &#8211; there is addressing within each
packet &#8211; so if the
hardware contention is resolved then multiple clients can exist on one drop
&#8211;
not too practical for RS232 I agree. But still as you say it could be done
even
with multiple clients on a drop. It is possible I guess that a bridge (or
more
likely router) could be maintained between networks over an asynch
connection &#8211;
if that happened the gateway would not now which devices to generate
heartbeats
for &nbsp;&#8211; in my adjacent post I raised a similar suggestion
(point 5) as a
workaround around for dumb devices. I added a <grimace> too as the
heartbeat was intended to show a device was alive and well which this
circumvents.</span></font></p>
<p class="MsoNormal"><font size="2"
color="navy"
face="Arial"><span>&nbsp;</span></font></p>
<p class="MsoNormal"><font size="2"
color="navy"
face="Arial"><span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Kevin</span></font></p>
<p class="MsoNormal"><font size="3"
face="Times New Roman"><span>
&nbsp;</span></font></p>
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